Attorneys took aim at BP, Transocean and cement contractor Halliburton, as well as other BP contractors, in an early effort to limit their own
liability.

Among the recurring story lines and accusations:

That BP, which held the lease on the Macondo well and oversaw drilling operations on Deepwater Horizon rig, was more concerned with profits than safety, as it ran behind schedule and over-budget on the well, and that BP rig supervisors had botched a crucial safety test before the 2010 drilling-platform explosion;

That Transocean, which owned the drilling rig and supplied both the rig and the crew to BP, had not properly trained its crew;

That Halliburton, which was hired by BP to pour the cement plugs in the Macondo well, used a type of cement that was known to be risky but did not succeed in sealing the well.

The outcome of the trial, potentially stretching for three months, could result in companies paying billions of dollars in fines for the explosion and collapse of the Deepwater Horizon rig in 2010, which killed 11 workers and caused one of the worst environmental disasters in U.S. history.

For BP and the other companies, the first phase of the court case focuses on whether their actions leading to the accident constitute gross negligence or willful misconduct. If U.S. District Court Judge Carl Barbier finds that the company deliberately ignored safety protocols, it would result in a four-fold increase in the billions of dollars of Clean Water Act penalties expected to be levied.

Michael Underhill, an attorney for the Justice Department, said that
"by far, the primary fault for this disaster lies with BP," and that decisions to proceed with drilling the well based on narrow margins and a risky
cement design all fell on the oil giant.

Underhill said the government's
case would demonstrate "a long series of missteps and reckless decisions
made by BP" that altogether demonstrate willful misconduct.

"The
evidence will show that BP put profits above people, profits before
safety and profits before the environment," he said.

Opening statements Monday morning included Underhill, as well as Jim Roy, co-lead counsel for the private plaintiffs who've filed suit against the oil giant. Alabama Attorney General Luther Strange and Louisiana Attorney General Buddy Caldwell also gave their presentations.

Brad Brian, lead counsel for Transocean, wrapped up the morning's arguments before court adjourned for lunch.

Roy wasted no time bringing Transocean into the fold. By his fourth sentence, Roy said the so-called negative pressure test, carried out by a Transocean crew being supervised by BP, was "a shared responsibility between BP and Transocean."

"This led to the mistaken belief that the well was secure and that it was safe to go forward with displacement of the heavy drill mud with much lighter seawater," Roy said.

Lifting the curtain on what's likely to be a key argument, Roy said an expert petroleum engineer for the plaintiffs would describe the failure to interpret the test as "a gross and extreme departure from the standards of good oilfield practice."

Much of his argument focused on Transocean not providing its crew with proper training for interpreting a negative test flow.

Transocean's crew didn't follow "basic well monitoring" processes and that company executives did not keep up on maintaining the rig, Roy said. The captain of the Deepwater Horizon was "woefully under-trained," he said. "Good guy, good captain, but under-trained in the safety management system."

Roy also contended that Transocean overrode several automatic functions of its alarm, requiring a crew member to manually activate the shutdown system, since it was designed to control safety-critical functions automatically. He said a Transocean chief electronics technician would testify that it was "done to avoid waking people up at night."

He also took aim at the blowout preventer, which failed to prevent the rig from exploding, could not handle the maximum pressure and temperature conditions for the Macondo well, and therefore should not have been used. He also said Transocean was not maintaining the drilling rig with much frequency.

"When the rig does receive maintenance time, that time is generally taken up by repairing the equipment that is broken," Roy said, adding that Transocean was "making over half a million dollars a day instead of bringing the vessel into a shipyard for repairs."

"Transocean's safety culture was broken, and the evidence will show that management's willful refusal to fix it led directly to the Deepwater Horizon disaster," he said.

He also turned his attention to Cameron International, the manufacturer of the blowout preventer, "the main barrier protecting human life." Roy spread the blame on the equipment's failure, saying it was due to "serious neglect of Transocean with knowledge of BP, but also due to willful decisions of Cameron." Bringing Halliburton in, Roy said the company used a type of cement that was known to have risks and required additional expertise, but that it was poorly designed and did not seal the well.

"Yet, despite knowing it was drilling the 'well from hell' ... BP barreled ahead and gambled with a piece of major equipment that was the last line of defense to protect against an uncontrolled blowout," Roy said.

Strange, the attorney general for Alabama who is handling the case for the states, turned the focus back at the British oil giant, calling the oil spill "both predictable and preventable," and blaming BP's "culture of corporate callousness towards the Gulf."

Like Roy, Strange said the corner cutting was motivated by profits, saying that "BP was blinded by their bottom-line."

Caldwell, Louisiana's attorney general, echoed that, describing the case as one that "is really about the cost of doing business, not just in the Gulf of Mexico but in the world."

"The disaster has damaged Louisiana's people, its economy, and it's ecology," he said. "But most importantly, this disaster continues in various forms," saying the company acted "grossly negligent manner."

BP is most likely to be charged the lion's share of the fines. Its
lead counsel, Rupert Bondy, said recently that he believes the company's
response to the accident, including early statements accepting
financial responsibility for valid damage claims, will help convince Barbier to charge BP much less than the maximum
allowed by law.

In pleading guilty to criminal environmental
charges in January, BP has already confirmed that its actions involving
the well were negligent. Transocean and the Justice Department also laid
most of the blame on BP in recent arguments supporting a similar plea
by Transocean to criminal environmental charges. The attorneys argued
that Transocean's negligence is overshadowed by BP's actions.

Brian, the lead counsel for Transocean, sought to minimize the role that his company's crew played in misreading the pressure test, instead pitting the responsibility on the onsite overseers, who were BP employees.

Brian described a phone call that took place between BP's onsite well site leader, Donald Vidrine, and Mark Hafle, their onshore engineer, at 8:53 p.m. on April 20, 2010, about an hour before the explosion. He said the conversation "explains virtually everything you need to know about what happened on the rig that night."

The pair had "multiple indications" from the negative testing that the cement barrier that's used to prevent oil or gas from flowing up the well was not secure. But they did not alert onshore engineers about the problems during the testing.

Vidrine and Robert Kaluza, the highest-ranking BP supervisors on the rig, were charged with manslaughter in a federal indictment unsealed in November. Hafle has not been charged.

"These men on the drill crew made the mistake of putting too much trust in BP," Brian said. "And they paid for that trust with their lives."

Brian said that while both BP and Transocean had plead guilty to criminal penalties, that's where the comparison ended. His argument kept circling back to whether the drill crew or the company that employed the crew was ultimately at fault for what happened.

Opening statements were slated to continue into Monday afternoon. Witness testimony is expected to begin on Tuesday.